Daily Question [October 22]

Does it refer to filling water into the lower part of the high-pressure washer before driving? If so, it indicates that the U-tube of the liquid outlet pipe is filled with water when the temperature of the liquid coming out of the high-pressure washer changes. However, during the water injection process, it is necessary to ensure that the U-tube discharge valve is closed. 1# Cherish Water

Changes in the liquid temperature at the bottom of the high-pressure washer generally indicate a decrease, which suggests that the washer is already filled with liquid and it is now possible to start operating the ammonia pump

This post was last edited by Xieshui on 2009-10-23 at 20:43. On the third floor, it’s possible to start using the ammonia pump. After adding ammonia, is it still necessary to add water? If so, what is the amount of water required in M3/H? What determines this amount, and how is the water added? Is it possible to operate without adding water?

This post was last edited by Hainachuanhe on 2009-12-21 at 23:35. 2# lxq700918

There are clear requirements in the operating procedures for urea production using the CO2 stripping method, including specifications regarding the timing and amount of water to be added. Friend upstairs, are you working in this industry?

6# Water conservation: Yes, our process (the steam stripping method using a urea production tower with a capacity of 1,620 tons per day) involves adding water to the high-pressure ammonium methoxide scrubber 1.5–2 hours after ammonia is introduced (at the lowest speed of the high-pressure ammonium methoxide pump). Due to the different process design conditions, the operations also vary. Your question is: In the initial startup of the CO2 stripping process (with an empty tower), how can the amount of water to be added to the high-pressure scrubber be determined? I work in the urea production industry. What I don’t understand is why water needs to be added before adding the materials What is the purpose? Adding water in advance will increase the amount of water in your system, which is detrimental to achieving the higher conversion rates that we aim for in normal operation of the reactor ； At the same time, during normal operation of the plant, the syngas entering the high-pressure washer has a low concentration of components and little ammonia content; adding water in advance will cause premature and excessive condensation in the high-pressure washer, which is detrimental to its explosion protection capabilities. If the hydrogen content in the feed gas is high, it further increases the likelihood of the material reaching its explosive limit. To this end, the operating procedures specify strictly the water addition time, the temperature of the temperature-regulated water on the shell side of the high-pressure washer (to be kept as high as possible), and the circulation time. The purpose is to reduce premature and excessive condensation in the high-pressure washer. I’m not sure if this answer can solve your question. The shortcomings should be addressed by the personnel incharge of the 1,620-ton urea process. If, as lxq700918 on the 2nd floor said, your goal is to direct the flow toward the U-tube in order to maintain the liquid seal, then in terms of process design, the high-pressure system has several discharge pipelines that are connected to the high-pressure flushing pump. Why not supply water from another source to maintain this liquid seal? Different process designs result in varying operations. I would appreciate your advice!

7# Haina Chuan River: The main purpose of adding water to the high-pressure washer is to absorb the gas phase from the synthesis tower and to lower the melting point of methammonium, thereby preventing crystallization. If no water is added, the gas entering the washer will consist only of NH3 + CO2 with no water present; in such a case, the temperature at which methammonium crystals form is 154°C, while the temperature of the water in the high-pressure system is only around 130°C. As a result, the gas coming from the synthesis tower will condense and crystallize inside the high-pressure washer. Therefore, water must be added to the high-pressure system before NH3 is introduced. The addition of a certain amount of water also enhances the condensation effect within the high-pressure system.

Based on the water-carbon ratio of the system, 70% of the CO2 is fed at full load. Calculate the amount of water to be added to the system’s high-pressure washer.

This post was last edited by Hainachuanhe on 2009-12-20 at 02:22. 8# Ran Hongyang: Fellow 8th-floor resident, I believe my viewpoint has been explained quite clearly in my reply! What I want to emphasize is that our processes are different, and so are our operations! In actual production, various operations are not only different from each other but also serve different purposes! What you advocate is precisely what our process is designed to prevent! But it should be asked: is pure (100%) methylammonium produced in the high-washing unit? The crystallization temperature of pure methylammonium is 154°C, which determines the lowest temperature at which production can take place in our high-pressure system; the design of the entire process is based on this temperature as one of its key parameters! This also specifies the reason why the system needs to be heated for passivation (another purpose of heating is to facilitate the formation of an oxide film)! Another point is that there is a temperature difference between the tube side and the shell side of the heat exchanger. According to your view, should the high-temperature water flow rate during operation be controlled at 154°C? I suggest checking out the book \"Urea Production Process and Operation\" edited by Yuan Yi, published by Sinopec Press, pages 140, 182, and 220

10# Haina Chuan River: No, it’s impossible for the water to be 100% pure, and there’s no need to raise the temperature of the water to such a high level. Do you never add water to the system when driving? What is the set temperature control for the coolant in your vehicle? How is crystallization prevented?